Simultaneous transmission in multiple frequency segments

ABSTRACT

A communication device generates a first packet for transmission in a first frequency segment, and generates a first physical layer (PHY) preamble of the first packet to include a first field that indicates a first overall bandwidth that the first packet spans. The communication device generates a second packet for transmission in a second frequency segment, and generates a second PHY preamble of the second packet to include a second field that indicates a second overall bandwidth that the second packet spans. The communication device transmits the first packet in the first frequency segment beginning at a first time, and simultaneously transmits the second packet in the second frequency segment beginning at a second time that is different than the first time.

CROSS REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/846,128 (now U.S. Pat. No. 11,178,630), entitled “SimultaneousTransmissions in Multiple Frequency Segments,” filed on Apr. 10, 2020,which claims the benefit of U.S. Provisional Patent Application No.62/832,757, entitled “Extra High Throughput (EHT) Aggregated PLCPProtocol Data Unit (PPDU),” filed on Apr. 11, 2019. Both of theapplication referenced above are incorporated herein by reference intheir entireties.

FIELD OF TECHNOLOGY

The present disclosure relates generally to wireless communicationsystems, and more particularly to data transmission and reception overmultiple communication channels.

BACKGROUND

Wireless local area networks (WLANs) have evolved rapidly over the pasttwo decades, and development of WLAN standards such as the Institute forElectrical and Electronics Engineers (IEEE) 802.11 Standard family hasimproved single-user peak data rates. One way in which data rates havebeen increased is by increasing the frequency bandwidth of communicationchannels used in WLANs. For example, the IEEE 802.11n Standard permitsaggregation of two 20 MHz sub-channels to form a 40 MHz aggregatecommunication channel, whereas the more recent IEEE 802.11ax Standardpermits aggregation of up to eight 20 MHz sub-channels to form up to 160MHz aggregate communication channels. Work has now begun on a newiteration of the IEEE 802.11 Standard, which is referred to as the IEEE802.11be Standard, or Extremely High Throughput (EHT) WLAN. The IEEE802.11be Standard may permit aggregation of as many as sixteen 20 MHzsub-channels (or perhaps even more) to form up to 320 MHz aggregatecommunication channels (or perhaps even wider aggregate communicationchannels). Additionally, the IEEE 802.11be Standard may permitaggregation 20 MHz sub-channels in different frequency segments (forexample, separated by a gap in frequency) to form a single aggregatechannel. Further, the IEEE 802.11be Standard may permit aggregation 20MHz sub-channels in different radio frequency (RF) bands to form asingle aggregate channel.

The current draft of the IEEE 802.11ax Standard (referred to herein as“the IEEE 802.11ax Standard” for simplicity) defines an “80+80”transmission mode in which a communication device simultaneouslytransmits in two 80 MHz channel segments within a single radio frequency(RF) band. The two 80 MHz channel segments may be separated in frequencywithin the single RF band. Transmissions in the two 80 MHz channelsegments are synchronized, i.e., the transmissions begin at a same starttime and end at a same end time.

SUMMARY

In an embodiment, a method for simultaneously transmitting in aplurality of frequency segments includes: generating, at a communicationdevice, a first packet for transmission in a first frequency segment,including generating a first physical layer (PHY) preamble of the firstpacket to include a first field that indicates a first overall bandwidththat the first packet spans; generating, at the communication device, asecond packet for transmission in a second frequency segment, includinggenerating a second PHY preamble of the second packet to include asecond field that indicates a second overall bandwidth that the secondpacket spans; and simultaneously transmitting, by the communicationdevice, the first packet in the first frequency segment and the secondpacket in the second frequency segment, including: transmitting thefirst packet in the first frequency segment beginning at a first time,and transmitting the second packet in the second frequency segmentbeginning at a second time that is different than the first time.

In another embodiment, a wireless communication device comprises awireless network interface device that includes: one or more integratedcircuit (IC) devices, and a plurality of radio frequency (RF) radiosincluding at least a first RF radio and a second RF radio. The pluralityof RF radios are implemented at least partially on the one or more ICdevices and are configured to: generate a first packet for transmissionin a first frequency segment, including generating a first PHY preambleof the first packet to include a first field that indicates a firstoverall bandwidth that the first packet spans; generate a second packetfor transmission in a second frequency segment, including generating asecond PHY preamble of the second packet to include a second field thatindicates a second overall bandwidth that the second packet spans; andcontrol the first RF radio and the second RF radio to simultaneouslytransmit the first packet in the first frequency segment and the secondpacket in the second frequency segment, including: controlling the firstRF radio to transmit the first packet in the first frequency segmentbeginning at a first time, and controlling the second RF radio totransmit the second packet in the second frequency segment beginning ata second time that is different than the first time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an example wireless local area network(WLAN) in which respective RF signals are simultaneously transmitted inrespective frequency segments.

FIG. 2A is a diagram of an example synchronized transmission overdifferent channel segments, according to an embodiment.

FIG. 2B is a diagram of an example unsynchronized transmission overdifferent channel segments, according to an embodiment.

FIG. 3A is a diagram of an example synchronized downlink multi-user (MU)orthogonal frequency division multiple access (OFDMA) transmission overdifferent channel segments, according to an embodiment.

FIG. 3B is a diagram of an example unsynchronized MU OFDMA transmissionover different channel segments, according to an embodiment.

FIG. 4 is a flow diagram of an example method for transmitting viamultiple frequency segments in a wireless communication network,according to an embodiment.

FIG. 5 is a diagram of an example network interface device configuredfor multi-channel segment operation, according to an embodiment.

FIG. 6A is a diagram of example packets transmitted in respectivefrequency segments, according to an embodiment.

FIG. 6B is a diagram of an example non-legacy preamble that is includedin the example packets of FIG. 6A, according to some embodiments.

DETAILED DESCRIPTION

A next generation wireless local area network (WLAN) protocol (e.g., theIEEE 802.11be Standard, sometimes referred to as the Extremely HighThroughput (EHT) WLAN Standard) may permit simultaneous transmissions indifferent channel segments. The different channel segments may be in asingle radio frequency (RF) band or in different RF bands. The differentchannel segments may have a same bandwidth or different bandwidths.

The IEEE 802.11ax Standard permits synchronized transmissions (i.e., thetransmissions begin at a same start time and end at a same end time) intwo 80 MHz channel segments (referred to as an “80+80) transmission),and requires that the two 80 MHz channel segments be idle at the sametime in order for the synchronized transmissions to proceed. Findingtimes when both 80 MHz channel segments are idle, however, is oftendifficult for many WiFi deployments, thus limiting the usefulness of the80+80 transmission mode.

In some embodiments described below, a communication device isconfigured to transmit synchronously in different channel segments(e.g., the transmissions begin at a same start time) in some scenarios,and to transmit asynchronously in different channel segments (e.g., thetransmissions are not required to begin at a same start time) in otherscenarios. Transmitting asynchronously in the different channel segmentsdoes not require that the different channel segments be idle at a sametime, at least in some embodiments, thus permitting simultaneous use ofthe different channel segments more frequently as compared to acommunication system that always requires that transmissions indifferent channel segments be synchronous (e.g., the transmissions beginat a same start time) and that the different channel segments be idle ata same time, at least in some embodiments and/or situations.

FIG. 1 is a block diagram of an example wireless local area network(WLAN) 110, according to an embodiment. The WLAN 110 includes an accesspoint (AP) 114 that comprises a host processor 118 coupled to a networkinterface device 122. The network interface device 122 includes one ormore medium access control (MAC) processors 126 (sometimes referred toherein as “the MAC processor 126” for brevity) and one or more physicallayer (PHY) processors 130 (sometimes referred to herein as “the PHYprocessor 130” for brevity). The PHY processor 130 includes a pluralityof transceivers 134, and the transceivers 134 are coupled to a pluralityof antennas 138. Although three transceivers 134 and three antennas 138are illustrated in FIG. 1 , the AP 114 includes other suitable numbers(e.g., 1, 2, 4, 5, etc.) of transceivers 134 and antennas 138 in otherembodiments. In some embodiments, the AP 114 includes a higher number ofantennas 138 than transceivers 134, and antenna switching techniques areutilized.

The network interface device 122 is implemented using one or moreintegrated circuits (ICs) configured to operate as discussed below. Forexample, the MAC processor 126 may be implemented, at least partially,on a first IC, and the PHY processor 130 may be implemented, at leastpartially, on a second IC. As another example, at least a portion of theMAC processor 126 and at least a portion of the PHY processor 130 may beimplemented on a single IC. For instance, the network interface device122 may be implemented using a system on a chip (SoC), where the SoCincludes at least a portion of the MAC processor 126 and at least aportion of the PHY processor 130.

In an embodiment, the host processor 118 includes a processor configuredto execute machine readable instructions stored in a memory device (notshown) such as a random access memory (RAM), a read-only memory (ROM), aflash memory, etc. In an embodiment, the host processor 118 may beimplemented, at least partially, on a first IC, and the network device122 may be implemented, at least partially, on a second IC. As anotherexample, the host processor 118 and at least a portion of the networkinterface device 122 may be implemented on a single IC.

In various embodiments, the MAC processor 126 and/or the PHY processor130 of the AP 114 are configured to generate data units, and processreceived data units, that conform to a WLAN communication protocol suchas a communication protocol conforming to the IEEE 802.11 Standard oranother suitable wireless communication protocol. For example, the MACprocessor 126 may be configured to implement MAC layer functions,including MAC layer functions of the WLAN communication protocol, andthe PHY processor 130 may be configured to implement PHY functions,including PHY functions of the WLAN communication protocol. Forinstance, the MAC processor 126 may be configured to generate MAC layerdata units such as MAC service data units (MSDUs), MAC protocol dataunits (MPDUs), aggregate MPDUs (A-MPDUs), etc., and provide the MAClayer data units to the PHY processor 130. MPDUs and A-MPDUs exchangedbetween the MAC processor 126 and the PHY processor 130 are sometimesreferred to as physical layer convergence procedure (PLCP) (or simply“PHY”) service data units (PSDUs).

The PHY processor 130 may be configured to receive MAC layer data units(or PSDUs) from the MAC processor 126 and encapsulate the MAC layer dataunits (or PSDUs) to generate PHY data units such as PLCP (or “PHY”)protocol data units (PPDUs) for transmission via the antennas 138.Similarly, the PHY processor 130 may be configured to receive PHY dataunits that were received via the antennas 138, and extract MAC layerdata units encapsulated within the PHY data units. The PHY processor 130may provide the extracted MAC layer data units to the MAC processor 126,which processes the MAC layer data units.

PHY data units are sometimes referred to herein as “packets”, and MAClayer data units are sometimes referred to herein as “frames”.

In connection with generating one or more radio frequency (RF) signalsfor transmission, the PHY processor 130 is configured to process (whichmay include modulating, filtering, etc.) data corresponding to a PPDU togenerate one or more digital baseband signals, and convert the digitalbaseband signal(s) to one or more analog baseband signals, according toan embodiment. Additionally, the PHY processor 130 is configured toupconvert the one or more analog baseband signals to one or more RFsignals for transmission via the one or more antennas 138.

In connection with receiving one or more signals RF signals, the PHYprocessor 130 is configured to downconvert the one or more RF signals toone or more analog baseband signals, and to convert the one or moreanalog baseband signals to one or more digital baseband signals. The PHYprocessor 130 is further configured to process (which may includedemodulating, filtering, etc.) the one or more digital baseband signalsto generate a PPDU.

The PHY processor 130 includes amplifiers (e.g., a low noise amplifier(LNA), a power amplifier, etc.), a radio frequency (RF) downconverter,an RF upconverter, a plurality of filters, one or more analog-to-digitalconverters (ADCs), one or more digital-to-analog converters (DACs), oneor more discrete Fourier transform (DFT) calculators (e.g., a fastFourier transform (FFT) calculator), one or more inverse discreteFourier transform (IDFT) calculators (e.g., an inverse fast Fouriertransform (IFFT) calculator), one or more modulators, one or moredemodulators, etc.

The PHY processor 130 is configured to generate one or more RF signalsthat are provided to the one or more antennas 138. The PHY processor 130is also configured to receive one or more RF signals from the one ormore antennas 138.

The MAC processor 126 is configured to control the PHY processor 130 togenerate one or more RF signals by, for example, providing one or moreMAC layer data units (e.g., MPDUs) to the PHY processor 130, andoptionally providing one or more control signals to the PHY processor130, according to some embodiments. In an embodiment, the MAC processor126 includes a processor configured to execute machine readableinstructions stored in a memory device (not shown) such as a RAM, a readROM, a flash memory, etc. In another embodiment, the MAC processor 126includes a hardware state machine.

The MAC processor 126 includes, or implements, a multi-channel segmenttransmission controller 142 that is configured to determine whentransmissions in different channel segments are to be transmittedsynchronously (e.g., the transmissions begin at a same start time), andwhen transmissions in different channel segments can be transmittedasynchronously (e.g., the transmissions are not required to begin at asame start time), according to an embodiment. When transmissions indifferent channel segments are to be transmitted synchronously, themulti-channel segment transmission controller 142 prompts the PHYprocessor 130 to begin the transmissions in the different channelsegments at a same time, according to some embodiments. Whentransmissions in different channel segments are to be transmittedasynchronously, the multi-channel segment transmission controller 142prompts the PHY processor 130 to begin the transmissions in thedifferent channel segments at different times, according to someembodiments.

In an embodiment, the multi-channel segment transmission controller 142is implemented by a processor executing machine readable instructionsstored in a memory, where the machine readable instructions cause theprocessor to perform acts described in more detail below. In anotherembodiment, the multi-channel segment transmission controller 142additionally or alternatively comprises hardware circuitry that isconfigured to perform acts described in more detail below. In someembodiments, the hardware circuitry comprises one or more hardware statemachines that are configured to perform acts described in more detailbelow.

The WLAN 110 includes a plurality of client stations 154. Although threeclient stations 154 are illustrated in FIG. 1 , the WLAN 110 includesother suitable numbers (e.g., 1, 2, 4, 5, 6, etc.) of client stations154 in various embodiments. The client station 154-1 includes a hostprocessor 158 coupled to a network interface device 162. The networkinterface device 162 includes one or more MAC processors 166 (sometimesreferred to herein as “the MAC processor 166” for brevity) and one ormore PHY processors 170 (sometimes referred to herein as “the PHYprocessor 170” for brevity). The PHY processor 170 includes a pluralityof transceivers 174, and the transceivers 174 are coupled to a pluralityof antennas 178. Although three transceivers 174 and three antennas 178are illustrated in FIG. 1 , the client station 154-1 includes othersuitable numbers (e.g., 1, 2, 4, 5, etc.) of transceivers 174 andantennas 178 in other embodiments. In some embodiments, the clientstation 154-1 includes a higher number of antennas 178 than transceivers174, and antenna switching techniques are utilized.

The network interface device 162 is implemented using one or more ICsconfigured to operate as discussed below. For example, the MAC processor166 may be implemented on at least a first IC, and the PHY processor 170may be implemented on at least a second IC. As another example, at leasta portion of the MAC processor 166 and at least a portion of the PHYprocessor 170 may be implemented on a single IC. For instance, thenetwork interface device 162 may be implemented using an SoC, where theSoC includes at least a portion of the MAC processor 166 and at least aportion of the PHY processor 170.

In an embodiment, the host processor 158 includes a processor configuredto execute machine readable instructions stored in a memory device (notshown) such as a RAM, a ROM, a flash memory, etc. In an embodiment, thehost processor 158 may be implemented, at least partially, on a firstIC, and the network device 162 may be implemented, at least partially,on a second IC. As another example, the host processor 158 and at leasta portion of the network interface device 162 may be implemented on asingle IC.

In various embodiments, the MAC processor 166 and the PHY processor 170of the client device 154-1 are configured to generate data units, andprocess received data units, that conform to the WLAN communicationprotocol or another suitable communication protocol. For example, theMAC processor 166 may be configured to implement MAC layer functions,including MAC layer functions of the WLAN communication protocol, andthe PHY processor 170 may be configured to implement PHY functions,including PHY functions of the WLAN communication protocol. The MACprocessor 166 may be configured to generate MAC layer data units such asMSDUs, MPDUs, etc., and provide the MAC layer data units to the PHYprocessor 170. The PHY processor 170 may be configured to receive MAClayer data units from the MAC processor 166 and encapsulate the MAClayer data units to generate PHY data units such as PPDUs fortransmission via the antennas 178. Similarly, the PHY processor 170 maybe configured to receive PHY data units that were received via theantennas 178, and extract MAC layer data units encapsulated within thePHY data units. The PHY processor 170 may provide the extracted MAClayer data units to the MAC processor 166, which processes the MAC layerdata units.

The PHY processor 170 is configured to downconvert one or more RFsignals received via the one or more antennas 178 to one or morebaseband analog signals, and convert the analog baseband signal(s) toone or more digital baseband signals, according to an embodiment. ThePHY processor 170 is further configured to process the one or moredigital baseband signals to demodulate the one or more digital basebandsignals and to generate a PPDU. The PHY processor 170 includesamplifiers (e.g., an LNA, a power amplifier, etc.), an RF downconverter,an RF upconverter, a plurality of filters, one or more ADCs, one or moreDACs, one or more DFT calculators (e.g., an FFT calculator), one or moreIDFT calculators (e.g., an IFFT calculator), one or more modulators, oneor more demodulators, etc.

The PHY processor 170 is configured to generate one or more RF signalsthat are provided to the one or more antennas 178. The PHY processor 170is also configured to receive one or more RF signals from the one ormore antennas 178.

The MAC processor 166 is configured to control the PHY processor 170 togenerate one or more RF signals by, for example, providing one or moreMAC layer data units (e.g., MPDUs) to the PHY processor 170, andoptionally providing one or more control signals to the PHY processor170, according to some embodiments. In an embodiment, the MAC processor166 includes a processor configured to execute machine readableinstructions stored in a memory device (not shown) such as a RAM, a ROM,a flash memory, etc. In an embodiment, the MAC processor 166 includes ahardware state machine.

In some embodiments, the MAC processor 166 includes a multi-channelsegment transmission controller (not shown) the same as or similar tothe multi-channel segment transmission controller 142 of the AP 114. Forexample, the client station 154-1 is configured transmit synchronouslyin different channel segments (e.g., the transmissions begin at a samestart time) in some scenarios, and to transmit asynchronously indifferent channel segments (e.g., the transmissions are not required tobegin at a same start time) in other scenarios, according to someembodiments.

In an embodiment, each of the client stations 154-2 and 154-3 has astructure that is the same as or similar to the client station 154-1.Each of the client stations 154-2 and 154-3 has the same or a differentnumber of transceivers and antennas. For example, the client station154-2 and/or the client station 154-3 each have only two transceiversand two antennas (not shown), according to an embodiment.

In an embodiment, multiple different frequency bands within the RFspectrum are employed for signal transmissions within the WLAN 110. Inan embodiment, different communication devices (i.e., the AP 114 and theclient stations 154) may be configured for operation in differentfrequency bands. In an embodiment, at least some communication devices(e.g., the AP 114 and the client station 154) in the WLAN 110 may beconfigured for simultaneous operation over multiple different frequencybands. Exemplary frequency bands include, a first frequency bandcorresponding to a frequency range of approximately 2.4 GHz-2.5 GHz (“2GHz band”), and a second frequency band corresponding to a frequencyrange of approximately 5 GHz-5.9 GHz (“5 GHz band”) of the RF spectrum.In an embodiment, one or more communication devices within the WLAN mayalso be configured for operation in a third frequency band in the 6GHz-7 GHz range (“6 GHz band”). Each of the frequency bands comprisemultiple component channels which may be combined within the respectivefrequency bands to generate channels of wider bandwidths, as describedabove. In an embodiment corresponding to multi-channel segment operationover a first channel segment and a second channel segment, the firstchannel segment and the second channel segment may be in separatefrequency bands, or within a same frequency band. In some embodiments,at least one communication device (e.g., at least the AP 114) in theWLAN 110 is configured for simultaneous operation over any two of the 2GHz band, the 5 GHz band, and the 7 GHz band. In some embodiments, atleast one communication device (e.g., at least the AP 114) in the WLAN110 is configured for simultaneous operation over all three of the 2 GHzband, the 5 GHz band, and the 7 GHz band.

FIG. 2A is a diagram of an example synchronized transmission 200 overdifferent channel segments, according to an embodiment. In anembodiment, the transmission 200 is generated and transmitted by thenetwork interface device 122 (FIG. 1 ) to one or more client stations154 (e.g., the client station 154-1). In another embodiment, thetransmission 200 is generated and transmitted by the network interfacedevice 162 (FIG. 1 ) to the AP 114.

In an embodiment, the transmission 200 corresponds to a single user (SU)transmission that is generated and transmitted to a single communicationdevice. In another embodiment, the transmission 200 corresponds to amulti-user (MU) transmission that includes data for multiplecommunication devices (e.g., multiple ones of the client stations 154).For example, in an embodiment, the MU transmission 200 is an OFDMAtransmission. In another embodiment, the MU transmission 200 is anMU-MIMO transmission.

The transmission 200 comprises a first RF signal 204 in a first channelsegment 208 and a second RF signal 212 in a second channel segment 216.The first RF signal 204 corresponds to a first PPDU and the second RFsignal 212 corresponds to a second PPDU, according to an embodiment. Thefirst signal comprises a PHY preamble 220 and a PHY data portion 224.The second signal 212 comprises of a PHY preamble 228, a data portion232, and optional padding 236. The transmission 200 is synchronized suchthat transmission of the first signal 204 and the second signal 212start at a same time t₁. In some embodiments, the first signal 204 andthe second signal 212 also end at a same time t₂.

In some embodiments, the PHY preamble 220 and the PHY preamble 228 arenot required to have a same duration and/or to end at a same time. Inother embodiments, the PHY preamble 220 and the PHY preamble 228 arerequired to have a same duration and/or to end at a same time.

In an embodiment in which the second RF signal 212 would otherwise havea shorter duration than the first RF signal 204, the PHY data portion232 is appended with a packet extension field 236 so that transmissionof the signal 212 ends at t₂. In an embodiment, the packet extensionfield 236 includes arbitrary data that is ignored by receivers.

In another embodiment in which the second RF signal 212 has a shorterduration than the first RF signal 204, duration information in a MACheader (not shown) within the PHY data portion 232 is set to indicatethat the transmission of the signal 212 ends at t₂, which causes anothercommunication device to set a network allocation vector (NAV) timer ofthe other communication device to a value that indicates transmission ofthe signal 212 will end at t₂.

In another embodiment in which the second RF signal 212 would otherwisehave a shorter duration than the first RF signal 204, paddinginformation is included in the PHY data portion 232 so that transmissionof the signal 212 ends at t₂.

Example formats of the PHY preamble 220 and the PHY preamble 228 aredescribed in more detail below. In an embodiment, at least a portion ofthe PHY preamble 220 and at least a portion of the PHY preamble 228include different information. In another embodiment, at least a portionof the PHY preamble 220 and at least a portion of the PHY preamble 228have the same structure and/or include the same information. In someembodiments, at least a portion of the PHY preamble 220 and at least aportion of the PHY preamble 228 are identical.

In an embodiment in which the first channel segment 208 comprisesmultiple component channels (e.g., 20 MHz subchannels), at least aportion of the PHY preamble 220 (e.g., a legacy portion) is generated bygenerating a field corresponding to one component channel andduplicating the field over one or more other component channelscorresponding to the first channel segment 208. In an embodiment inwhich the second channel segment 216 comprises multiple componentchannels (e.g., 20 MHz subchannels), at least a portion of the PHYpreamble 228 (e.g., a legacy portion) is generated by generating a fieldcorresponding to one component channel and duplicating the field overone or more other component channels corresponding to the second channelsegment 216.

In various embodiments, the first channel segment 208 and the secondchannel segment 216 are in different RF bands or are co-located in asame RF band. In an embodiment, the RF band(s) correspond to the 2 GHzband, the 5 GHz band, and the 6 GHz bands, as described above. The firstchannel segment 208 and the second channel segment 216 may each becomprised of one or more of component channels. In an embodiment, afrequency bandwidth of the first channel segment 208 (i.e., a frequencybandwidth of the first signal 204) is different than a frequencybandwidth of the second channel segment 216 (i.e., a frequency bandwidthof the second signal 212). In another embodiment, the frequencybandwidth of the first channel segment 208 is the same as the frequencybandwidth of the second channel segment 216.

In an embodiment, the first channel segment 208 and the second channelsegment 216 are separated in frequency. For example, a gap in frequencyexists between the first channel segment 208 and the second channelsegment 216. In various embodiments, the gap is at least 500 kHz, atleast 1 MHz, at least 5 MHz, at least 20 MHz, etc.

In some embodiments, the first signal 204 is transmitted via a firstnumber of spatial or space-time streams (hereinafter referred to as“spatial streams” for brevity), and the second signal 212 is transmittedvia a second number of spatial streams that is different than the firstnumber of spatial streams. In one such embodiment, the PHY preamble 220includes a first number of LTFs corresponding to the first number ofspatial streams, and the PHY preamble 228 includes a second number ofLTFs (different than the first number of LTFs) corresponding to thesecond number of spatial streams. In another such embodiment, the PHYpreamble 220 and the PHY preamble 228 comprise a same number of LTFseven when the first signal 204 is transmitted via a first number ofspatial streams and the second signal 212 is transmitted via a secondnumber of spatial streams that is different than the first number ofspatial streams. In an embodiment, the same number of LTFs correspond toone of the first signal 204 and the second signal 212 with the largernumber of spatial streams. In other embodiments, the first signal 204and the second signal 212 are transmitted via a same number of spatialstreams.

In an embodiment, at least the PHY data portion 224 and at least the PHYdata portion 232 employ different encoding schemes and/or modulationschemes. As an example, in an embodiment, the PHY data portion 224 isgenerated using a first MCS and the PHY data portion 432 is generatedusing a second, different MCS. In other embodiments, the PHY dataportion 224 and the PHY data portion 232 are generated using a same MCS.

In an embodiment, the transmission 200 corresponds to a single PPDU,where a first frequency portion of the single PPDU is transmitted viathe first channel 208 and a second frequency portion of the single PPDUis transmitted via the second channel 216. In another embodiment, thefirst signal 204 corresponds to a first PPDU and the second signal 212corresponds to a second PPDU. In an embodiment, each of the PHYpreambles 220 and 228, and the PHY data portions 224 and 232, arecomprised of one or more OFDM symbols.

FIG. 2B is a diagram of an example unsynchronized transmission 250 overdifferent channel segments, according to an embodiment. In anembodiment, the transmission 250 is generated and transmitted by thenetwork interface device 122 (FIG. 1 ) to one or more client stations154 (e.g., the client station 154-1). In another embodiment, thetransmission 250 is generated and transmitted by the network interfacedevice 162 (FIG. 1 ) to the AP 114.

The unsynchronized transmission 250 is similar to the synchronizedtransmission 200 of FIG. 2A, and like-numbered elements are notdescribed in detail for brevity. Unlike the synchronized transmission200 of FIG. 2A, transmission of the signal 204 and transmission of thesignal 212 begin at different times. Additionally, transmission of thesignal 204 and transmission of the signal 212 end at different times,according to some embodiments. Further, the signal 212 does not includethe packet extension field 236 of FIG. 2A, according to someembodiments.

Referring now to FIGS. 1 and 2A-B, a communication device (e.g., the AP114, the client station 154-1, etc.) is configured to generate andtransmit a synchronized transmission such as the transmission 200 (FIG.2A) at some times (and/or in some scenarios), and to generate andtransmit an unsynchronized transmission such as the transmission 250(FIG. 2B) at other times (and/or in other scenarios), according to someembodiments. For example, transmitting an unsynchronized transmission indifferent channel segments does not require that the different channelsegments be idle at a same time, at least in some embodiments, thuspermitting simultaneous use of the different channel segments when asynchronized transmission may not be possible (e.g., when thesynchronized transmission requires that the different channel segmentsare idle at the same time), at least in some embodiments and/orsituations. On the other hand, unsynchronized transmissions in thedifferent channel segments may not be permitted in some scenarios, suchas when the different channel segments are relatively close infrequency, at least in some embodiments and/or situations.

FIG. 3A is a diagram of an example synchronized downlink MU OFDMAtransmission 300 over different channel segments, according to anembodiment. In an embodiment, the transmission 300 is generated andtransmitted by the network interface device 122 (FIG. 1 ) to a pluralityof client stations 154.

The OFDMA transmission 300 comprises a first RF signal 304 in a firstchannel segment 308 and a second RF signal 312 in a second channelsegment 316. In various embodiments, the first channel segment 308 andthe second channel segment 316 are similar to the first channel segment208 and the second channel segment 216, respectively, as described abovewith reference FIG. 2A. The transmission 300 is synchronized such thatthe first RF signal 304 and the second RF signal 312 start at a sametime t₁. In some embodiments, the first RF signal 304 and the second RFsignal 312 end at a same time t₂.

The first signal 304 comprises a PHY preamble 320 and a PHY data portion324. The second signal 312 comprises of a PHY preamble 328 and a dataportion 332. In some embodiments, the PHY preamble 320 and the PHYpreamble 328 are not required to have a same duration and/or to end at asame time. In other embodiments, the PHY preamble 320 and the PHYpreamble 328 are required to have a same duration and/or to end at asame time.

In an embodiment in which the second RF signal 312 would otherwise havea shorter duration than the first RF signal 304, the PHY data portion332 is appended with a packet extension field 336 so that transmissionof the signal 312 ends at t₂. In an embodiment, the packet extensionfield 336 includes arbitrary data that is ignored by receivers.

In another embodiment in which the second RF signal 312 has a shorterduration than the first RF signal 304, duration information in a MACheader (not shown) within the PHY data portion 332 is set to indicatethat the transmission of the signal 312 ends at t₂, which causes anothercommunication device to set a NAV timer of the other communicationdevice to a value that indicates transmission of the signal 212 will endat t₂.

In another embodiment in which the second RF signal 312 would otherwisehave a shorter duration than the f first RF signal 304, paddinginformation is included in the PHY data portion 332 so that transmissionof the signal 312 ends at t₂.

In an embodiment, the PHY preamble 320 and the PHY preamble 328 areformatted in a manner similar to the PHY preamble 204. Example formatsof the PHY preamble 320 and the PHY preamble 328 are described in moredetail below. In an embodiment, at least a portion of the PHY preamble320 and at least a portion of the PHY preamble 328 include differentinformation. In another embodiment, at least a portion of the PHYpreamble 320 and at least a portion of the PHY preamble 328 have thesame structure and/or include the same information. In some embodiments,at least a portion of the PHY preamble 320 and at least a portion of thePHY preamble 328 are identical.

In an embodiment in which the first channel segment 308 comprisesmultiple component channels (e.g., 20 MHz subchannels), at least aportion of the PHY preamble 320 (e.g., a legacy portion) is generated bygenerating a field corresponding to one component channel andduplicating the field over one or more other component channelscorresponding to the first channel segment 308. In an embodiment inwhich the second channel segment 316 comprises multiple componentchannels, at least a portion of the PHY preamble 328 (e.g., a legacyportion) is generated by generating a field corresponding to onecomponent channel and duplicating the field over one or more othercomponent channels corresponding to the second channel segment 316.

In various embodiments, the first channel segment 308 and the secondchannel segment 316 are in different RF bands or are co-located in asame RF band. In an embodiment, the RF band(s) correspond to the 2 GHzband, the 5 GHz band, and the 6 GHz bands, as described above. The firstchannel segment 308 and the second channel segment 316 may each becomprised of one or more of component channels. In an embodiment, afrequency bandwidth of the first channel segment 308 (i.e., a frequencybandwidth of the first signal 304) is different than a frequencybandwidth of the second channel segment 316 (i.e., a frequency bandwidthof the second signal 212). In another embodiment, the frequencybandwidth of the first channel segment 308 is the same as the frequencybandwidth of the second channel segment 316.

In an embodiment, the first communication channel 308 and the secondcommunication channel 316 are separated in frequency. For example, a gapin frequency exists between the first communication channel 308 and thesecond communication channel 316. In various embodiments, the gap is atleast 500 kHz, at least 1 MHz, at least 5 MHz, at least 20 MHz, etc.

In some embodiments, the first signal 304 is transmitted via a firstnumber of spatial streams, and the second signal 312 is transmitted viaa second number of spatial streams that is different than the firstnumber of spatial streams. In one such embodiment, the PHY preamble 320includes a first number of LTFs corresponding to the first number ofspatial streams, and the PHY preamble 328 includes a second number ofLTFs (different than the first number of LTFs) corresponding to thesecond number of spatial streams. In another such embodiment, the PHYpreamble 320 and the PHY preamble 328 comprise a same number of LTFseven when the first signal 304 is transmitted via a first number ofspatial streams and the second signal 312 is transmitted via a secondnumber of spatial streams that is different than the first number ofspatial streams. In an embodiment, the same number of LTFs correspond toone of the first signal 304 and the second signal 312 with the largernumber of spatial streams. In other embodiments, the first signal 304and the second signal 312 are transmitted via a same number of spatialstreams.

In an embodiment, at least a PHY data portion 324 and at least a PHYdata portion 332 employ different encoding schemes and/or modulationschemes.

In an embodiment, the transmission 300 corresponds to a single PPDU,where a first frequency portion of the single PPDU is transmitted viathe first channel 308 and a second frequency portion of the single PPDUis transmitted via the second channel 316. In another embodiment, thefirst signal 304 corresponds to a first PPDU and the second signal 312corresponds to a second PPDU. In an embodiment, each of the PHYpreambles 320 and 328, and the PHY data portions 324 and 332, arecomprised of one or more OFDM symbols.

The PHY data portion 324 and the PHY data portion 332 include respectivefrequency multiplexed data for respective client stations 154.Individual data within the data portion 324 are transmitted tocorresponding client stations 154 in corresponding allocated frequencyresource units (RUs) 340. Individual data within the data portion 332are transmitted to corresponding client stations 154 in correspondingallocated RUs 344. In various embodiments, transmitted signalscorresponding to some or all of RUs 340/344 use different encodingschemes and/or modulation schemes. As an example, transmitted signalscorresponding to the RU 340-1 and the RU 344-1 are generated usingdifferent MCSs and/or different numbers of spatial/space-time streams,etc. In an embodiment in which a duration of data in an RU 344 isshorter than a duration of the PHY data portion 324, padding is added tothe data in the RU 344 to ensure the duration of the PHY data portionsin both communication channels are the same.

In at least some embodiments, at least some of the client stations 154are configured to operate only in one RF band. In such embodiments, RUsare allocated to the client station 154 only within the RF band in whichthe client station 154 is configured to operate. As an illustrativeembodiment, STA2 and STA3 are configured to operate only in a first RFband. Hence, data corresponding to STA2 and STA3 is transmitted over RUswithin the first channel segment 308, which is within the first RF bandin an embodiment. Similarly, STA4 is configured to operate only in asecond RF band. Hence, data corresponding to STA4 is transmitted overRUs within the second channel segment 316, which is within the second RFband in an embodiment. On the other hand, STA1 is configured foroperation in both the first RF band and the second RF band. Hence, datacorresponding to STA1 may be transmitted in RUs located in either orboth of the first channel segment 308 and the second channel segment316.

FIG. 3B is a diagram of an example unsynchronized MU OFDMA transmission350 over different channel segments, according to an embodiment. In anembodiment, the transmission 350 is generated and transmitted by thenetwork interface device 122 (FIG. 1 ) to one or more client stations154 (e.g., the client station 154-1). In another embodiment, thetransmission 350 is generated and transmitted by the network interfacedevice 162 (FIG. 1 ).

The unsynchronized transmission 350 is similar to the synchronizedtransmission 300 of FIG. 2A, and like-numbered elements are notdescribed in detail for brevity. Unlike the synchronized transmission300 of FIG. 3A, transmission of the signal 304 and transmission of thesignal 312 begin at different times. Additionally, transmission of thesignal 304 and transmission of the signal 312 end at different times,according to some embodiments. Further, the signal 312 does not includethe packet extension field 336 of FIG. 3A, according to someembodiments.

Referring now to FIGS. 1 and 3A-B, a communication device (e.g., the AP114, the client station 154-1, etc.) is configured to generate andtransmit a synchronized transmission such as the transmission 300 (FIG.3A) at some times (and/or in some scenarios), and to generate andtransmit an unsynchronized transmission such as the transmission 350(FIG. 3B) at other times (and/or in other scenarios), according to someembodiments.

FIG. 4 is a flow diagram of an example method 400 for transmitting viamultiple frequency segments in a wireless communication network,according to an embodiment. The AP 114 of FIG. 1 is configured toimplement the method 400, according to some embodiments. The clientstation 154-1 of FIG. 1 is additionally or alternatively configured toimplement the method 400, according to other embodiments. The method 400is described in the context of the AP 114 merely for explanatorypurposes and, in other embodiments, the method 400 is implemented by theclient station 154-1 or another suitable communication device, accordingto various embodiments.

At block 404, a communication device determines (e.g., the AP 114determines, the network interface 122 determines, the MAC processor 126determines, the multi-channel segment transmission controller 142determines, etc.) whether simultaneous respective transmissions in aplurality of frequency segments are to be synchronized (e.g., thesimultaneous respective transmissions are to begin at a same time). Invarious embodiments, the plurality of frequency segments are contiguousin frequency, or one or more adjacent pairs of frequency segments areseparated in frequency by a respective gap in frequency. In variousembodiments, each frequency segment in the plurality of frequencysegments spans a same frequency bandwidth, or frequency segments in theplurality of frequency segments span different frequency bandwidths. Invarious embodiments, two or more frequency segments in the plurality offrequency segments are in a same RF band (e.g., the 2 GHz band, the 5GHz band, the 6 GHz band, etc.), or two or more frequency segments inthe plurality of frequency segments are in different RF bands.

In various embodiments, determining whether the simultaneous respectivetransmissions are to be synchronized at block 404 is based on a varietyof parameters and/or factors. For example, in one embodiment,determining whether the simultaneous respective transmissions are to besynchronized at block 404 is based on a bandwidth of a frequency gapbetween adjacent frequency segments in the plurality of frequencysegments. For instance, when a frequency gap between a first frequencysegment and a second frequency segment is less than a threshold, thecommunication device determines (e.g., the AP 114 determines, thenetwork interface 122 determines, the MAC processor 126 determines,etc.) at block 404 that the simultaneous transmissions in the firstfrequency segment and the second frequency segment are to besynchronized (e.g., the simultaneous respective transmissions are tobegin at a same time); whereas when the frequency gap between the firstfrequency segment and the second frequency segment is greater than thethreshold, the communication device determines (e.g., the AP 114determines, the network interface 122 determines, the MAC processor 126determines, etc.) at block 404 that the simultaneous transmissions inthe first frequency segment and the second frequency segment are notrequired to be synchronized, according to an illustrative embodiment.When the first frequency segment and the second frequency segment arerelatively close in frequency (e.g., the frequency gap between the firstfrequency segment and the second frequency segment is less than thethreshold), an amount (or probability) of inter-channel interference isrelatively high, and thus requiring synchronized transmissions improvesperformance (e.g., overall throughput); whereas when the first frequencysegment and the second frequency segment are relatively far apart infrequency (e.g., the frequency gap between the first frequency segmentand the second frequency segment is greater than the threshold), theamount (or probability) of inter-channel interference is relatively low,and thus requiring synchronized transmissions is not required, accordingto an illustrative embodiment.

As another example, in another embodiment, determining whether thesimultaneous respective transmissions are to be synchronized at block404 is additionally or alternatively based on bandwidth capabilities ofone or more other communication devices that are to receive thesimultaneous respective transmissions. For instance, in response to theAP 114 determining (e.g., the network interface 122 determines, the MACprocessor 126 determines, etc.) that one or more of the othercommunication devices are not capable of receiving unsynchronizedtransmissions, the AP 114 determines at block 404 that the simultaneousrespective transmissions in the plurality of frequency segments are tobe synchronized, according to an illustrative embodiment.

As another example, determining whether the simultaneous respectivetransmissions are to be synchronized at block 404 is based on an overallfrequency bandwidth of the plurality of frequency segments in theplurality of frequency segments. For instance, when the overallbandwidth is less than a threshold, the communication device determines(e.g., the AP 114 determines, the network interface 122 determines, theMAC processor 126 determines, etc.) at block 404 that the simultaneoustransmissions in the first frequency segment and the second frequencysegment are to be synchronized (e.g., the simultaneous respectivetransmissions are to begin at a same time); whereas when the overallbandwidth is greater than the threshold, the communication devicedetermines (e.g., the AP 114 determines, the network interface 122determines, the MAC processor 126 determines, etc.) at block 404 thatthe simultaneous transmissions in the first frequency segment and thesecond frequency segment are not required to be synchronized, accordingto an illustrative embodiment. When the overall bandwidth is relativelynarrow (e.g., the overall bandwidth is less than the threshold), theprobability of finding times when all frequency segments in theplurality of frequency segments are idle is relatively high and benefitsof synchronized transmissions may improve performance (e.g., overallthroughput); whereas when the overall bandwidth is relatively wide(e.g., the overall bandwidth is greater than the threshold), theprobability of finding times when all frequency segments in theplurality of frequency segments are idle is relatively low and benefitsof synchronized transmissions will not outweigh performance degradationdue increased failures to find times when all frequency segments areidle, according to an illustrative embodiment.

When it is determined at block 404 that simultaneous respectivetransmissions in the plurality of frequency segments are to besynchronized, the flow proceeds to block 408. At block 408, the AP 114simultaneously transmits (e.g., the network interface device 122simultaneously transmits, the PHY processor 130 simultaneouslytransmits, etc.) via the plurality of frequency segments in asynchronized manner. Simultaneously transmitting at block 408 comprisestransmitting a first signal via a first frequency segment at a firsttime, and transmitting a second signal via a second frequency segment atthe first time, according to an embodiment.

In some embodiments, prior to simultaneously transmitting in asynchronized manner at block 408, the AP 114 determines (e.g., thenetwork interface device 122 determines, the MAC processor 126determines, etc.) when the plurality of frequency segments are idle at asame time, and begins the simultaneous, synchronous transmission atblock 408 after determining that the plurality of frequency segments areidle at the same time. In some embodiments, prior to simultaneouslytransmitting in a synchronized manner at block 408, the AP 114 waits(e.g., the network interface device 122 waits, the MAC processor 126waits, etc.) until the plurality of frequency segments are alldetermined to be idle at the same time, and then begins thesimultaneous, synchronous transmission at block 408.

In some embodiments, simultaneously transmitting at block 408 comprisestransmitting signals such as described above with reference to FIG. 2A.In other embodiments, simultaneously transmitting at block 408 comprisestransmitting signals such as described above with reference to FIG. 3A.In other embodiments, simultaneously transmitting at block 408 comprisestransmitting other suitable signals having other suitable formats.

In some embodiments, simultaneously transmitting at block 408 comprisesthe multi-channel segment transmission controller 142 prompting the PHYprocessor 130 to begin the first transmission in the first frequencysegment at the first time and to begin the second transmission in thesecond frequency segment at the first time.

On the other hand, when it is determined at block 404 that simultaneousrespective transmissions in the plurality of frequency segments are tobe unsynchronized, the flow proceeds to block 412. Simultaneouslytransmitting at block 412 comprises transmitting a third signal via athird frequency segment at a second time, and transmitting a fourthsignal via a fourth frequency segment at a third time, according to anembodiment. In some embodiments, the third frequency segment is thefirst frequency segment (block 408), and the fourth frequency segment isthe second frequency segment (block 408), according to an embodiment.

In some embodiments, unlike the synchronous transmissions at block 408,the AP 114 does not need to determine when the plurality of frequencysegments are idle at a same time, or wait for a time when the pluralityof frequency segments are idle at a same time, before a transmission atblock 412 in one of the frequency segments can begin. For example, whenthe AP 114 determines (e.g., the network interface device 122determines, the MAC processor 126 determines, etc.) that a firstfrequency segment among the plurality of frequency segments is idle, theAP 114 can begin transmitting (at block 412) in the first frequencysegment even though the AP 114 determines (e.g., the network interfacedevice 122 determines, the MAC processor 126 determines, etc.) that asecond frequency segment among the plurality of frequency segments isnot also idle at the same time, according to an embodiment. When the AP114 later determines the second frequency segment has also become idle,the AP 114 can begin transmitting (at block 412) in the second frequencysegment simultaneously with the transmission (at block 412) in the firstfrequency segment.

In some embodiments, simultaneously transmitting at block 412 comprisestransmitting signals such as described above with reference to FIG. 2B.In other embodiments, simultaneously transmitting at block 412 comprisestransmitting signals such as described above with reference to FIG. 3B.In other embodiments, simultaneously transmitting at block 412 comprisestransmitting other suitable signals having other suitable formats.

In some embodiments, simultaneously transmitting at block 412 comprisesthe multi-channel segment transmission controller 142 prompting the PHYprocessor 130 to begin the third transmission in the third frequencysegment at the second time and to begin the fourth transmission in thefourth frequency segment at the third time.”

In some embodiments, the first frequency segment is the same as thethird frequency segment, and the second frequency segment is the same asthe fourth frequency segment. In other embodiments, the first frequencysegment is different from the third frequency segment, and/or the secondfrequency segment is different from the fourth frequency segment.

In some embodiments, the first packet is the same as the third packet,and the second packet is the same as the fourth packet. In otherembodiments, the first packet is different from the third packet, and/orthe second packet is different from the fourth packet.

FIG. 5 is a diagram of an example network interface device 500configured for multi-channel segment operation, according to anembodiment. For instance, in an embodiment, the network interface device500 is configured for synchronous and/or asynchronoustransmission/reception over multiple frequency segments. In anembodiment, the network interface device 500 corresponds to the networkinterface device 122 of the AP 114 of FIG. 1 . In another embodiment,the network interface device 500 corresponds to the network interfacedevice 162 of the client station 154-1 of FIG. 1 .

The network interface device 500 is configured for operation over twofrequency segments. The network interface device 500 includes a MACprocessor 508 coupled to a PHY processor 516. The MAC processor 508exchanges frames (or PSDUs) with the PHY processor 516.

In an embodiment, the MAC processor 508 corresponds to the MAC processor126 of FIG. 1 . In another embodiment, the MAC processor 508 correspondsto the MAC processor 166 of FIG. 1 . In an embodiment, the PHY processor516 corresponds to the PHY processor 130 of FIG. 1 . In anotherembodiment, the PHY processor 516 corresponds to the PHY processor 170of FIG. 1 .

The PHY processor 516 includes a single baseband signal processor 520.The single baseband signal processor 520 is coupled to a first RF radio(Radio-1) 528 and a second RF radio (Radio-2) 536. In an embodiment, theRF radio 528 and the RF radio 536 correspond to the transceivers 134 ofFIG. 1 . In another embodiment, the RF radio 528 and the RF radio 536correspond to the transceivers 174 of FIG. 1 . In an embodiment, the RFradio 528 is configured to operate on a first RF band, and the RF radio536 is configured to operate on a second RF band. In another embodiment,the RF radio 528 and the RF radio 536 are both configured to operate onthe same RF band.

In an embodiment, the MAC processor 508 generates data corresponding toMAC layer data units (e.g., frames) and provides the frames (or PSDUs)to the baseband signal processor 520. The baseband signal processor 520is configured to receive frames (or PSDUs) from the MAC processor 508,and encapsulate the frames (or PSDUs) into respective packets andgenerate respective baseband signals corresponding to the respectivepackets. The baseband signal processor 520 provides the respectivebaseband signals to the Radio-1 528 and the Radio-2 536. The Radio-1 528and Radio-2 536 upconvert the respective baseband signals to generaterespective RF signals for transmission via the first frequency segmentand the second frequency segment, respectively. The Radio-1 528transmits a first RF signal via the first frequency segment and theRadio-2 536 transmits a second RF signal via the second frequencysegment.

In some embodiments, the MAC processor 508 determines whether frames areto be transmitted synchronously or asynchronously, and informs thebaseband signal processor 520 whether the frames are to be transmittedsynchronously or asynchronously when providing the frames to thebaseband signal processor 520. In some embodiments, the MAC processor508 determines in which frequency segment a frame is to be transmitted,and informs the baseband signal processor 520 of the frequency segmentin which the frame is to be transmitted when providing the frame to thebaseband signal processor 520.

When the first RF signal and the second RF signal are to besynchronized, the baseband signal processor 520 is configured to ensurethat respective transmitted signals over the first frequency segment andthe second frequency segment are synchronized. For example, the basebandsignal processor 520 is provide the respective baseband signals to theRadio-1 528 and the Radio-2 536 beginning at a same time.

The Radio-1 528 and the Radio-2 536 are also configured to receiverespective RF signals via the first frequency segment and the secondfrequency segment, respectively. The Radio-1 528 and the Radio-2 536generate respective baseband signals corresponding to the respectivereceived signals. The generated respective baseband signals are providedto the baseband signal processor 520. The baseband signal processor 520generates respective PSDUs corresponding to the respective receivedsignals, and provides the PSDUs to the MAC processor 508. The MACprocessor 508 processes the PSDUs received from the baseband signalprocessor 520.

FIG. 6A is a diagram of example PPDUs 604 and 608 transmitted inrespective frequency segments, according to an embodiment. For example,PPDU 604 is transmitted in a first frequency segment and PPDU 608 istransmitted in a second frequency segment. In some embodiments and/orscenarios, the first frequency segment is separated in frequency fromthe second frequency segment by a gap in frequency. In other embodimentsand/or scenarios, the first frequency segment is adjacent in frequencyto the second frequency segment, and the first frequency segment is notseparated in frequency from the second frequency segment.

In some embodiments, the PHY processor 130 (FIG. 1 ) is configured togenerate and transmit the PPDUs 604 and 608. In some embodiments, thePHY processor 170 (FIG. 1 ) is configured to generate and transmit thePPDUs 604 and 608. In some embodiments, the baseband processor 520 (FIG.5 ) is configured to generate the PPDUs 604 and 608 and the radios 528,536 (FIG. 5 ) are configured to transmit the PPDUs 604 and 608.

The PPDU 604 includes a legacy PHY preamble 612 (sometimes referred toas a legacy preamble 612), a non-legacy PHY preamble (e.g., an EHTpreamble) 616, and a PHY data portion 620. The legacy preamble 612comprises a legacy short training field (L-STF) 624, a legacy longtraining field (L-LTF) 628, and a legacy signal field (L-SIG) 632. TheL-SIG 632 includes a rate subfield (not shown) and a length subfield(not shown) that together indicate a duration of the PPDU 604. In someembodiments, the EHT preamble 616 includes PHY parameters regarding thePPDU 604 that are for use by receiver devices to properly process thePPDU 604, such as a modulation and coding scheme (MCS) subfield thatindicates an MCS used for the PHY data portion 620. When the PPDU 604 isan MU PPDU, the EHT preamble 616 includes allocation information thatindicates frequency resource unit (RU) allocation information, spatialstream allocation information, etc. In some embodiments, the EHTpreamble 616 includes one or more long training fields, the number ofwhich varies depending on how many spatial streams are used to transmitthe PHY data portion 620.

The PPDU 608 includes a legacy preamble 642, a non-legacy PHY preamble(e.g., an EHT preamble) 646, and a PHY data portion 650. The legacypreamble 642 comprises an L-STF 654, an L-LTF 658, and an L-SIG 632. TheL-SIG 632 includes a rate subfield (not shown) and a length subfield(not shown) that together indicate a duration of the PPDU 608. In someembodiments, the EHT preamble 646 includes PHY parameters regarding thePPDU 608 that are for use by receiver devices to properly process thePPDU 608, such as an MCS subfield that indicates an MCS used for the PHYdata portion 650. When the PPDU 608 is an MU PPDU, the EHT preamble 646includes allocation information that indicates frequency RU allocationinformation, spatial stream allocation information, etc. In someembodiments, the EHT preamble 646 includes one or more long trainingfields, the number of which varies depending on how many spatial streamsare used to transmit the PHY data portion 650.

In some embodiments in which transmission of the PPDU 604 and the PPDU608 is synchronized, the PPDU 608 includes a packet extension field 668so that a duration of the PPDU 608 is the same as a duration of the PPDU604. In other embodiments, the PHY data portion 650 additionally oralternatively includes padding as discussed above. In other embodiments,a signal extension is additionally or alternatively used for PPDU 608 sothat receiver devices set their NAV counters to a value that indicates aduration that corresponds to a duration of the PPDU 604 as discussedabove. In some embodiments in which transmission of the PPDU 604 and thePPDU 608 is asynchronous, the PPDU 608 does not include the packetextension field 668.

In some embodiments, a duration of the EHT preamble 616 is different (oris not required to be the same) as a duration of the EHT preamble 646.In other embodiments, the duration of the EHT preamble 616 is requiredto be the same as the duration of the EHT preamble 646 (e.g., paddingbits are added (if needed) to the EHT preamble 646 so that a duration ofthe EHT preamble 646 is the same as the duration of the EHT preamble616).

In embodiments in which the PPDU 604 has a different duration than thePPDU 608, the L-SIG 632 includes different information than the L-SIG662. For example, the length subfield in the L-SIG 632 indicates adifferent length than the length subfield in the L-SIG 662.

FIG. 6B is a diagram of an example non-legacy preamble (e.g., an EHTpreamble) 674 that is used as the non-legacy preamble 616 or thenon-legacy preamble 646, according to some embodiments.

In some embodiments, the PHY processor 130 (FIG. 1 ) is configured togenerate the non-legacy preamble 674. In some embodiments, the PHYprocessor 170 (FIG. 1 ) is configured to generate the non-legacypreamble 674. In some embodiments, the baseband processor 520 (FIG. 5 )is configured to generate the non-legacy preamble 674.

The non-legacy preamble 674 includes a first signal field (EHT-SIGA)678, a second signal field (EHT-SIGB) 682, a short training field(EHT-STF) 686, and one or more long training fields (EHT-LTFs) 690. Inan embodiment, when a PHY data portion corresponding to the non-legacypreamble 674 is to be transmitted via n spatial streams (where n is asuitable positive integer), the non-legacy preamble 674 includes no morethan n EHT-LTFs 690. In another embodiment, when a PHY data portioncorresponding to the non-legacy preamble 674 is to be transmitted via nspatial streams, the non-legacy preamble 674 includes at least nEHT-LTFs 690.

In some embodiments, EHT-SIGB 682 is included for MU PPDUs and is notincluded for single user (SU) PPDUs.

In various embodiments, the EHT-SIGA 678 and/or the EHT-SIGB 682indicate an MCS (or multiple MCSs for an MU PPDU) used for the PHY dataportion corresponding to the non-legacy preamble 674. Thus, whendifferent MCSs are used for different frequency segments, content of theEHT-SIGAs 678 in the different frequency segments is different.

Similarly, when different numbers of spatial streams are used fordifferent frequency segments, the number of EHT-LTFs 690 in thedifferent frequency segments is different, at least in some embodiments.

Referring now to FIGS. 6A-B, in embodiments in which the L-SIG 632 andthe L-SIG 662 include different information, a duplicate of the L-SIG632 is transmitted in each subchannel (e.g., each 20 MHz subchannel) ofthe first frequency segment, and a duplicate of the L-SIG 662 istransmitted in each subchannel (e.g., each 20 MHz subchannel) of thesecond frequency segment. In embodiments in which one or moresubchannels in a frequency segment are punctured (e.g., not used fortransmission), a duplicate of the L-SIG 632/662 is not transmitted inpunctured subchannels.

In embodiments in which the non-legacy signal field 678 includesdifferent information in different frequency segments, a duplicate ofthe non-legacy signal field 678 that includes information for the firstfrequency segment is transmitted in each subchannel (e.g., each 20 MHzsubchannel) of the first frequency segment, and a duplicate of thenon-legacy signal field 678 that includes information for the secondfrequency segment is transmitted in each subchannel (e.g., each 20 MHzsubchannel) of the second frequency segment. In embodiments in which oneor more subchannels in a frequency segment are punctured (e.g., not usedfor transmission), a duplicate of the non-legacy signal field 678 is nottransmitted in punctured subchannels.

Similarly, in embodiments in which the non-legacy signal field 682includes different information in different frequency segments, aduplicate of the non-legacy signal field 682 that includes informationfor the first frequency segment is transmitted in each subchannel (e.g.,each 20 MHz subchannel) of the first frequency segment, and a duplicateof the non-legacy signal field 682 that includes information for thesecond frequency segment is transmitted in each subchannel (e.g., each20 MHz subchannel) of the second frequency segment. In embodiments inwhich one or more subchannels in a frequency segment are punctured(e.g., not used for transmission), a duplicate of the non-legacy signalfield 682 is not transmitted in punctured subchannels.

In some embodiments (e.g., in which the PPDU 604 is a MU PPDU and thePPDU 608 is an SU PPDU), a duplicate of the non-legacy signal field 682that includes information for the first frequency segment is transmittedin each subchannel (e.g., each 20 MHz subchannel) of the first frequencysegment, and the non-legacy signal field 682 is not transmitted in thesecond frequency segment.

In some embodiments, the non-legacy signal field 678 includes abandwidth subfield 694 that indicates an overall bandwidth of only thefrequency segment in which the PPDU 604/608 is transmitted. For example,when the PPDU 604 is transmitted in a first frequency segment having anoverall bandwidth of 160 MHz and the PPDU 608 is transmitted in a secondfrequency segment having an overall bandwidth of 40 MHz, the bandwidthsubfield 694 in the PPDU 604 indicates a bandwidth of 160 MHz, whereasthe bandwidth subfield 694 in the PPDU 608 indicates a bandwidth of 40MHz.

In some embodiments, the non-legacy signal field 678 includes afrequency segment identifier (ID) subfield 698 that indicates thefrequency segment in which the PPDU 604/608 is transmitted. For example,when the PPDU 604 is transmitted in a first frequency segment and thePPDU 608 is transmitted in a second frequency segment, the frequencysegment ID subfield 698 in the PPDU 604 indicates the first frequencysegment, whereas the frequency segment ID subfield 698 in the PPDU 608indicates the second frequency segment.

In some embodiments, the non-legacy signal field 678 also includes oneor more other subfields (not shown) that indicate one or more of: i)whether a simultaneous transmission is occurring in any other frequencysegment(s), ii) a number of other frequency segments in which thesimultaneous transmission is occurring, iii) respective overallfrequency bandwidth(s) of the other frequency segment(s), and iv) acumulative frequency bandwidth of all of the frequency segments in whichsimultaneous transmissions are occurring.

In some embodiments, legacy preambles and non-legacy preambles havingformats such as discussed above with reference to FIGS. 6A-B are usedwith the transmissions discussed above with reference to FIGS. 2A-B and3A-B.

Although certain orderings of fields and subfields are illustrated inFIGS. 6A-B, in other embodiments, other suitable orderings fields andsubfields are utilized. In other embodiments, PHY preambles include oneor more other suitable fields/subfields in addition to the fields andsubfields illustrated in FIGS. 6A-B. Similarly, in some embodiments, oneor more of the fields/subfields illustrated in FIGS. 6A-B are omitted.

Embodiment 1: A method for simultaneously transmitting in a plurality offrequency segments, comprising: determining, at a communication device,whether simultaneous transmissions in a first frequency segment and asecond frequency segment are to be synchronized in time; in response tothe communication device determining that simultaneous transmissions inthe first frequency segment and the second frequency segment are to besynchronized in time, transmitting a first packet in the first frequencysegment beginning at a first time, and transmitting a second packet inthe second frequency segment beginning at the first time; and inresponse to the communication device determining that simultaneoustransmissions in the first frequency segment and the second frequencysegment are to be unsynchronized in time, transmitting a third packet inthe first frequency segment beginning at a second time, and transmittinga fourth packet in the second frequency segment beginning at a thirdtime that is different than the second time.

Embodiment 2. The method of embodiment 1, wherein determining whethersimultaneous transmissions in the first frequency segment and the secondfrequency segment are to be synchronized in time comprises: determiningwhether simultaneous transmissions in the first frequency segment andthe second frequency segment are to be synchronized in time based on afrequency bandwidth of a frequency gap between the first frequencysegment and the second frequency segment.

Embodiment 3. The method of embodiment 2, wherein determining whethersimultaneous transmissions in the first frequency segment and the secondfrequency segment are to be synchronized in time comprises: comparing,at the communication device, the frequency bandwidth of the frequencygap to a threshold; determining that simultaneous transmissions in thefirst frequency segment and the second frequency segment are to besynchronized in time in response to determining that the frequencybandwidth of the frequency gap is less than the threshold; anddetermining that simultaneous transmissions in the first frequencysegment and the second frequency segment are to be unsynchronized intime in response to determining that the frequency bandwidth of thefrequency gap is greater than the threshold.

Embodiment 4. The method of either of embodiments 1 or 2, whereindetermining whether simultaneous transmissions in the first frequencysegment and the second frequency segment are to be synchronized in timecomprises: determining whether simultaneous transmissions in the firstfrequency segment and the second frequency segment are to besynchronized in time based on capabilities of one or more othercommunication devices that are to receive the simultaneoustransmissions.

Embodiment 5. The method of embodiment 4, wherein determining whethersimultaneous transmissions in the first frequency segment and the secondfrequency segment are to be synchronized in time comprises: determiningwhether any of the one or more other communication devices are notcapable of processing unsynchronized transmissions in multiple frequencysegments; determining that simultaneous transmissions in the firstfrequency segment and the second frequency segment are to besynchronized in time in response to determining that at least one of theone or more other communication devices is not capable of processingunsynchronized transmissions in multiple frequency segments; anddetermining that simultaneous transmissions in the first frequencysegment and the second frequency segment are to be unsynchronized intime in response to determining that all of the one or more othercommunication devices are capable of processing unsynchronizedtransmissions in multiple frequency segments.

Embodiment 6. The method of any of embodiments 1, 2, or 4, whereindetermining whether simultaneous transmissions in the first frequencysegment and the second frequency segment are to be synchronizedcomprises: determining whether simultaneous transmissions in the firstfrequency segment and the second frequency segment are to besynchronized based on one or more of i) an overall frequency bandwidthof the first frequency segment, ii) an overall frequency bandwidth ofthe second frequency segment, and iii) a cumulative frequency bandwidthof the overall frequency bandwidth of the first frequency segment andthe overall frequency bandwidth of the second frequency segment.

Embodiment 7. The method of any of embodiments 1-6, further comprising:generating the first packet to have a first physical layer (PHY)preamble with a first duration; and generating the second packet to havea second PHY preamble with a second duration that is different than thefirst duration.

Embodiment 8. The method of embodiment 7, further comprising: generatingthe first PHY preamble to include different information than the secondPHY preamble.

Embodiment 9. The method of any of embodiments 1-8, generating thesecond packet comprises: generating the second packet to include apacket extension field so that transmission of the second packet endswhen transmission of the first packet ends.

Embodiment 10. The method of any of embodiments 1-9, wherein: when thefirst packet and the second packet are transmitted: generating, at thecommunication device, a first medium access control (MAC) layer dataunit, generating the first packet to include the first MAC layer dataunit, generating, at the communication device, a second MAC layer dataunit, generating the second packet to include the second MAC layer dataunit; and when the third packet and the fourth packet are transmitted:generating, at the communication device, a third MAC layer data unit,generating the third packet to include the third MAC layer data unit,generating, at the communication device, a fourth MAC layer data unit,and generating the second packet to include the fourth MAC layer dataunit.

Embodiment 11. The method of any of embodiments 1-10, wherein: when thefirst packet and the second packet are transmitted: transmitting thefirst packet via a first number of spatial streams, and transmitting thesecond packet via a second number of spatial streams that is differentthan the first number of spatial streams; and when the third packet andthe fourth packet are transmitted: transmitting the third packet via athird number of spatial streams, and transmitting the fourth packet viaa fourth number of spatial streams that is different than the thirdnumber of spatial streams.

Embodiment 12. A communication device, comprising: a wireless networkinterface device comprising: one or more integrated circuit (IC)devices, and a plurality of radio frequency (RF) radios including atleast a first RF radio and a second RF radio, wherein the plurality ofRF radios are implemented at least partially on the one or more ICdevices; wherein the one or more IC devices are configured to implementany of the methods of embodiments 1-11.

Embodiment 13. A communication device, comprising: a wireless networkinterface device comprising: one or more integrated circuit (IC)devices, and a plurality of radio frequency (RF) radios including atleast a first RF radio and a second RF radio, wherein the plurality ofRF radios are implemented at least partially on the one or more ICdevices. The one or more IC devices are configured to: determine whethersimultaneous transmissions in a first frequency segment and a secondfrequency segment are to be synchronized; and in response to thecommunication device determining that simultaneous transmissions in thefirst frequency segment and the second frequency segment are to besynchronized, control the first RF radio to transmit a first packet inthe first frequency segment beginning at a first time, and control thesecond RF radio to transmit a second packet in the second frequencysegment beginning at the first time. The one or more IC devices arefurther configured to: in response to the communication devicedetermining that simultaneous transmissions in the first frequencysegment and the second frequency segment are to be unsynchronized,control the first RF radio to transmit a third packet in the firstfrequency segment beginning at a second time, and control the second RFradio to transmit a fourth packet in the second frequency segmentbeginning at a third time that is different than the second time.

Embodiment 14. The communication device of embodiment 13, wherein theone or more IC devices are further configured to: determine whethersimultaneous transmissions in the first frequency segment and the secondfrequency segment are to be synchronized based on a frequency bandwidthof a frequency gap between the first frequency segment and the secondfrequency segment.

Embodiment 15. The communication device of embodiment 14, wherein theone or more IC devices are further configured to: compare the frequencybandwidth of the frequency gap to a threshold; determine thatsimultaneous transmissions in the first frequency segment and the secondfrequency segment are to be synchronized in response to determining thatthe frequency bandwidth of the frequency gap is less than the threshold;and determine that simultaneous transmissions in the first frequencysegment and the second frequency segment are to be unsynchronized inresponse to determining that the frequency bandwidth of the frequencygap is greater than the threshold.

Embodiment 16. The communication device of any of embodiments 13-15,wherein the one or more IC devices are further configured to: determinewhether simultaneous transmissions in the first frequency segment andthe second frequency segment are to be synchronized based oncapabilities of one or more other communication devices that are toreceive the simultaneous transmissions.

Embodiment 17. The communication device of any of embodiments 13-16,wherein the one or more IC devices are further configured to: determinewhether simultaneous transmissions in the first frequency segment andthe second frequency segment are to be synchronized based on one or moreof i) an overall frequency bandwidth of the first frequency segment, ii)an overall frequency bandwidth of the second frequency segment, and iii)a cumulative frequency bandwidth of the overall frequency bandwidth ofthe first frequency segment and the overall frequency bandwidth of thesecond frequency segment.

Embodiment 18. The communication device of any of embodiments 13-17,wherein the one or more IC devices are further configured to: generatethe first packet to have a first physical layer (PHY) preamble with afirst duration; and generate the second packet to have a second PHYpreamble with a second duration that is different than the firstduration.

Embodiment 19. The communication device of claim 18, wherein the one ormore IC devices are further configured to: generate the first PHYpreamble to include different information than the second PHY preamble.

Embodiment 20. The communication device of any of embodiments 13-19,wherein the one or more IC devices are further configured to: generatethe second packet to include a packet extension field so thattransmission of the second packet ends when transmission of the firstpacket ends.

Embodiment 21. The communication device of any of embodiments 13-20,wherein the one or more IC devices are further configured to: when thefirst packet and the second packet are transmitted: generate a firstmedium access control (MAC) layer data unit, generate the first packetto include the first MAC layer data unit, generate a second MAC layerdata unit, and generate the second packet to include the second MAClayer data unit. The one or more IC devices are further configured to:when the third packet and the fourth packet are transmitted: generate athird MAC layer data unit, generate the third packet to include thethird MAC layer data unit, generate a fourth MAC layer data unit, andgenerate the second packet to include the fourth MAC layer data unit.

Embodiment 22. The communication device of embodiment 21, wherein thewireless network interface device comprises: a single media accesscontrol (MAC) layer processor implemented on the one or more IC devices;a baseband signal processor implemented on the one or more IC devices,wherein the baseband signal processor is coupled to the single MACprocessor and to the plurality of RF radios; and wherein when the firstpacket and the second packet are transmitted: the single MAC layerprocessor is configured to generate the first MAC layer data unit andthe second MAC layer data unit, and the baseband processor is configuredto generate the first packet and the second packet; wherein when thethird packet and the fourth packet are transmitted: the single MAC layerprocessor is configured to generate the third MAC layer data unit andthe fourth MAC layer data unit, and the baseband processor is configuredto generate the third packet and the fourth packet.

Embodiment 23. The communication device of any of embodiments 13-122,wherein the one or more IC devices are further configured to: when thefirst packet and the second packet are transmitted: control the first RFradio to transmit the first packet via a first number of spatialstreams, and control the second RF radio to transmit the second packetvia a second number of spatial streams that is different than the firstnumber of spatial streams; and when the third packet and the fourthpacket are transmitted: control the first RF radio to transmit the thirdpacket via a third number of spatial streams, and control the second RFradio to transmit the fourth packet via a fourth number of spatialstreams that is different than the third number of spatial streams.

At least some of the various blocks, operations, and techniquesdescribed above may be implemented utilizing hardware, a processorexecuting firmware instructions, a processor executing softwareinstructions, or any combination thereof. When implemented utilizing aprocessor executing software or firmware instructions, the software orfirmware instructions may be stored in any computer readable memory suchas on a magnetic disk, an optical disk, or other storage medium, in aRAM or ROM or flash memory, processor, hard disk drive, optical diskdrive, tape drive, etc. The software or firmware instructions mayinclude machine readable instructions that, when executed by one or moreprocessors, cause the one or more processors to perform various acts.

When implemented in hardware, the hardware may comprise one or more ofdiscrete components, an integrated circuit, an application-specificintegrated circuit (ASIC), a programmable logic device (PLD), etc.

While the present invention has been described with reference tospecific examples, which are intended to be illustrative only and not tobe limiting of the invention, changes, additions and/or deletions may bemade to the disclosed embodiments without departing from the scope ofthe invention.

What is claimed is:
 1. A method for simultaneously transmitting in aplurality of frequency segments, comprising: generating, at acommunication device, a first packet for transmission in a firstfrequency segment, including generating a first physical layer (PHY)preamble of the first packet to include a first field that indicates afirst overall bandwidth that the first packet spans; generating, at thecommunication device, a second packet for transmission in a secondfrequency segment, including generating a second PHY preamble of thesecond packet to include a second field that indicates a second overallbandwidth that the second packet spans; and simultaneously transmitting,by the communication device, the first packet in the first frequencysegment and the second packet in the second frequency segment,including: transmitting the first packet in the first frequency segmentbeginning at a first time, and transmitting the second packet in thesecond frequency segment beginning at a second time that is differentthan the first time.
 2. The method of claim 1, wherein: generating thefirst packet comprises generating the first PHY preamble of the firstpacket to further include a third field that indicates the firstfrequency segment in which the first packet is being transmitted; andgenerating the second packet comprises generating the second PHYpreamble of the second packet to further include a fourth field thatindicates the second frequency segment in which the second packet isbeing transmitted.
 3. The method of claim 1, further comprising:generating the first PHY preamble with a first duration; and generatingthe second PHY preamble with a second duration that is different thanthe first duration.
 4. The method of claim 1, wherein: generating thefirst packet comprises: generating the first packet to have a firstduration, and generating the first PHY preamble to include a firstlegacy signal field that indicates the first duration; and generatingthe second packet comprises: generating the second packet to have asecond duration that is different than the first duration, andgenerating the second PHY preamble to include a second legacy signalfield that indicates the second duration.
 5. The method of claim 1,wherein simultaneously transmitting the first packet in the firstfrequency segment and the second packet in the first frequency segmentcomprises: transmitting the first packet via a first number of spatialstreams; and transmitting the second packet via a second number ofspatial streams that is different than the first number of spatialstreams.
 6. The method of claim 1, further comprising: determining, atthe communication device, whether simultaneous transmissions in thefirst frequency segment and the second frequency segment are to besynchronized in time; wherein transmitting the first packet in the firstfrequency segment beginning at the first time, and transmitting thesecond packet in the second frequency segment beginning at the secondtime, are in response to determining that simultaneous transmissions inthe first frequency segment and the second frequency segment are to beunsynchronized in time.
 7. The method of claim 6, wherein determiningwhether simultaneous transmissions in the first frequency segment andthe second frequency segment are to be synchronized in time comprises:determining whether simultaneous transmissions in the first frequencysegment and the second frequency segment are to be synchronized in timebased on a frequency bandwidth of a frequency gap between the firstfrequency segment and the second frequency segment.
 8. The method ofclaim 7, wherein determining whether simultaneous transmissions in thefirst frequency segment and the second frequency segment are to besynchronized in time comprises: comparing, at the communication device,the frequency bandwidth of the frequency gap to a threshold; determiningthat simultaneous transmissions in the first frequency segment and thesecond frequency segment are to be synchronized in time in response todetermining that the frequency bandwidth of the frequency gap is lessthan the threshold; and determining that simultaneous transmissions inthe first frequency segment and the second frequency segment are to beunsynchronized in time in response to determining that the frequencybandwidth of the frequency gap is greater than the threshold.
 9. Themethod of claim 6, wherein determining whether simultaneoustransmissions in the first frequency segment and the second frequencysegment are to be synchronized in time comprises: determining whethersimultaneous transmissions in the first frequency segment and the secondfrequency segment are to be synchronized in time based on capabilitiesof one or more other communication devices that are to receive thesimultaneous transmissions.
 10. The method of claim 9, whereindetermining whether simultaneous transmissions in the first frequencysegment and the second frequency segment are to be synchronized in timecomprises: determining whether any of the one or more othercommunication devices are not capable of processing unsynchronizedtransmissions in multiple frequency segments; determining thatsimultaneous transmissions in the first frequency segment and the secondfrequency segment are to be synchronized in time in response todetermining that at least one of the one or more other communicationdevices is not capable of processing unsynchronized transmissions inmultiple frequency segments; and determining that simultaneoustransmissions in the first frequency segment and the second frequencysegment are to be unsynchronized in time in response to determining thatall of the one or more other communication devices are capable ofprocessing unsynchronized transmissions in multiple frequency segments.11. The method of claim 6, wherein determining whether simultaneoustransmissions in the first frequency segment and the second frequencysegment are to be synchronized comprises: determining whethersimultaneous transmissions in the first frequency segment and the secondfrequency segment are to be synchronized based on one or more of i) anoverall frequency bandwidth of the first frequency segment, ii) anoverall frequency bandwidth of the second frequency segment, and iii) acumulative frequency bandwidth of the overall frequency bandwidth of thefirst frequency segment and the overall frequency bandwidth of thesecond frequency segment.
 12. A wireless communication device,comprising: a wireless network interface device including: one or moreintegrated circuit (IC) devices, and a plurality of radio frequency (RF)radios including at least a first RF radio and a second RF radio,wherein the plurality of RF radios are implemented at least partially onthe one or more IC devices; wherein the one or more IC devices areconfigured to: generate a first packet for transmission in a firstfrequency segment, including generating a first physical layer (PHY)preamble of the first packet to include a first field that indicates afirst overall bandwidth that the first packet spans, generate a secondpacket for transmission in a second frequency segment, includinggenerating a second PHY preamble of the second packet to include asecond field that indicates a second overall bandwidth that the secondpacket spans, and control the first RF radio and the second RF radio tosimultaneously transmit the first packet in the first frequency segmentand the second packet in the second frequency segment, including:controlling the first RF radio to transmit the first packet in the firstfrequency segment beginning at a first time, and controlling the secondRF radio to transmit the second packet in the second frequency segmentbeginning at a second time that is different than the first time. 13.The wireless communication device of claim 12, wherein the one or moreIC devices are configured to: generate the first PHY preamble of thefirst packet to further include a third field that indicates the firstfrequency segment in which the first packet is being transmitted; andgenerate the second PHY preamble of the second packet to further includea fourth field that indicates the second frequency segment in which thesecond packet is being transmitted.
 14. The wireless communicationdevice of claim 12, wherein the one or more IC devices are furtherconfigured to: generate the first PHY preamble with a first duration;and generate the second PHY preamble with a second duration that isdifferent than the first duration.
 15. The wireless communication deviceof claim 12, wherein the one or more IC devices are further configuredto: generate the first packet to have a first duration; generate thesecond packet to have a second duration that is different than the firstduration; generate the first PHY preamble to include a first legacysignal field that indicates the first duration; and generate the secondPHY preamble to include a second legacy signal field that indicates thesecond duration.
 16. The wireless communication device of claim 12,wherein the one or more IC devices are further configured to: controlthe first RF radio to transmit the first packet via a first number ofspatial streams; and control the first RF radio to transmit the secondpacket via a second number of spatial streams that is different than thefirst number of spatial streams.
 17. The wireless communication deviceof claim 12, wherein the one or more IC devices are further configuredto: determine whether simultaneous transmissions in the first frequencysegment and the second frequency segment are to be synchronized in time;and transmit the first packet in the first frequency segment beginningat the first time, and transmit the second packet in the secondfrequency segment beginning at the second time, in response todetermining that simultaneous transmissions in the first frequencysegment and the second frequency segment are to be unsynchronized intime.
 18. The wireless communication device of claim 17, wherein the oneor more IC devices are further configured to: determine whethersimultaneous transmissions in the first frequency segment and the secondfrequency segment are to be synchronized in time based on a frequencybandwidth of a frequency gap between the first frequency segment and thesecond frequency segment.
 19. The wireless communication device of claim18, wherein the one or more IC devices are further configured to:compare the frequency bandwidth of the frequency gap to a threshold;determine that simultaneous transmissions in the first frequency segmentand the second frequency segment are to be synchronized in time inresponse to determining that the frequency bandwidth of the frequencygap is less than the threshold; and determine that simultaneoustransmissions in the first frequency segment and the second frequencysegment are to be unsynchronized in time in response to determining thatthe frequency bandwidth of the frequency gap is greater than thethreshold.
 20. The wireless communication device of claim 17, whereinthe one or more IC devices are further configured to: determine whethersimultaneous transmissions in the first frequency segment and the secondfrequency segment are to be synchronized in time based on capabilitiesof one or more other communication devices that are to receive thesimultaneous transmissions.
 21. The wireless communication device ofclaim 20, wherein the one or more IC devices are further configured to:determine whether any of the one or more other communication devices arenot capable of processing unsynchronized transmissions in multiplefrequency segments; determine that simultaneous transmissions in thefirst frequency segment and the second frequency segment are to besynchronized in time in response to determining that at least one of theone or more other communication devices is not capable of processingunsynchronized transmissions in multiple frequency segments; anddetermine that simultaneous transmissions in the first frequency segmentand the second frequency segment are to be unsynchronized in time inresponse to determining that all of the one or more other communicationdevices are capable of processing unsynchronized transmissions inmultiple frequency segments.
 22. The wireless communication device ofclaim 17, wherein the one or more IC devices are further configured to:determine whether simultaneous transmissions in the first frequencysegment and the second frequency segment are to be synchronized based onone or more of i) an overall frequency bandwidth of the first frequencysegment, ii) an overall frequency bandwidth of the second frequencysegment, and iii) a cumulative frequency bandwidth of the overallfrequency bandwidth of the first frequency segment and the overallfrequency bandwidth of the second frequency segment.